Tristan Mahr

Tristan Mahr

Language and data scientist

Curriculum vitae

Education

  • 2018 - Ph.D., Communication Sciences and Disorders, University of Wisconsin–Madison.
  • 2013 - M.S., Speech-Language Pathology, University of Wisconsin–Madison.
  • 2009 - B.S., Linguistics and English, University of Wisconsin–Madison.

Current position

Data scientist - Wisconsin Intelligibility, Speech and Communication Laboratory

I study how children with cerebral palsy learn to talk and communicate. The project has amassed nearly 15 years of longitudinal speech and language data from children with cerebral palsy, and I analyze the developmental trajectories of these children. We also have collected data on nearly 600 typically developing children, and I developed quantile growth curves for features of these children’s speech. My work involves a mix of data programming, corpus phonetics, and statistical modeling and reporting.

Statistical consulting - Freelance.

I have consulted on generalized mixed-effects models and Bayesian regression models. I fit models and visualize data from psychology experiments. I deliver reproducible analyses with tutorials/commentary on the analysis steps and code. (Get in touch.)

Previous positions

Research assistant - Little Listeners project.

I prepared and analyzed eyetracking data from a series of word recognition experiments with toddlers. I also developed R packages for handling, visualizing and modeling these data, including a web-based interactive dashboard.

Research assistant - Learning to Talk project.

This project was a three-year longitudinal study of preschoolers done in collaboration by three universities. I was responsible for data organization, validation, automation and general data-cleaning tasks for the project. I developed R packages to automate these validation and back-up tasks, and I developed a MySQL database supporting R package for our data. I analyzed eyetracking and speech perception experiments from this project.

Programming and statistics

Languages: Mastery of R. Regular practice writing SQL, HTML/CSS, XML, YAML, Stan. Some practice with Java, JavaScript and Python. Exposure to Clojure.

Computing tools and technologies: bash/batch scripting, git and GitHub, tidy data and the R tidyverse, targets/drake workflows, Shiny, knitr/rmarkdown, Jekyll, Docker, Praat, makefiles, regular expressions.

Statistics: Regression: generalized linear models, hierarchical and mixed effects models, generalized additive models, and Bayesian versions of these models. Nonlinear regression models. Structural equation modeling and factor analysis. Neural networks: practice with shallow networks, familiarity with how some deep network architectures work (CNNs, RBMs, RNNs, denoising autoencoders).

Software

bayesplot. R package for visualizing Bayesian models and MCMC samples. It is the plotting library for the Stan programming language.

readtextgrid. R package for reading in Praat textgrids.

iccbot. A Shiny app for computing intraclass correlation coefficients as a reliability measure.

rprime. R package for working Eprime text files.

polypoly. Tools for orthogonal polynomials.

littlelisteners. A general-purpose R package for dealing with eyetracking data.

lookr. R package for dealing with eyetracking data for the Learning To Talk lab.

L2TDatabase. R package for working with the Learning To Talk lab’s MySQL database. Helper functions for creating, updating, backing-up MySQL tables in R.

adventofcode17. Completed a series of programming puzzles in R.

Plus, countless other R packages for various projects or problems.

I have also peer-reviewed software:

Publications

Mahr, T., & Hustad, K. C. (2023). Lexical Predictors of Intelligibility in Young Children’s Speech. Journal of Speech, Language, and Hearing Research, 66, 3013–3025. 10.1044/2022_JSLHR-22-00294. [🔓 Open Access.]

Soriano, J. U., Mahr, T., Rathouz, P. J., & Hustad, K. C. (2023). Intelligibility in Context Scale: Growth Curves for Typically Developing English-Speaking Children Between Ages 2;6 and 9;11. American Journal of Speech-Language Pathology, 32, 2021–2039. 10.1044/2023_AJSLP-22-00392. [🔓 Open Access.]

Hustad, K. C., Mahr, T., Soriano, J. U., & Rathouz, P. J. (2023). Developmental Cut-Points for Atypical Speech Intelligibility in Children With Cerebral Palsy. Journal of Speech, Language, and Hearing Research, 66, 3089–3099. 10.1044/2023_AJSLP-22-00392. [🔓 Open Access.]

Long, H. L., Mahr, T., Natzke, P. E. M., Rathouz, P. J., & Hustad, K. C. (2022). Longitudinal change in speech classification between 4 and 10 years in children with cerebral palsy. Developmental Medicine & Child Neurology, 64, 1096–1105. 10.1111/dmcn.15198. [🔓 Open Access.]

Sakash, A., Mahr, T., & Hustad, K. C. (2022). Perceptual measurement of articulatory goodness in young children: Relationships with age, speech sound acquisition, and intelligibility. Clinical Linguistics & Phonetics, 37, 1141–1156. 10.1080/02699206.2022.2150893.

Mahr, T., Soriano, J. U., Rathouz, P. J., & Hustad, K. C. (2021). Speech Development Between 30 and 119 Months in Typical Children II: Articulation Rate Growth Curves. Journal of Speech, Language, and Hearing Research, 64, 4057–4070. 10.1044/2021_JSLHR-21-00206. [🔓 Open Access. 📄 Preprint.]

Hustad, K. C., Mahr, T., Natzke, P. E. M., & Rathouz, P. J. (2021). Speech Development Between 30 and 119 Months in Typical Children I: Intelligibility Growth Curves for Single-Word and Multiword Productions. Journal of Speech, Language, and Hearing Research, 64, 3707–3719. 10.1044/2021_JSLHR-21-00142. [🔓 Open Access. ⭐ ASHA Journals’ most read article of 2021. 📰 Summary by The Informed SLP.]

Mahr, T., Berisha, V., Kawabata, K., Liss, J., & Hustad, K. C. (2021). Performance of Forced-Alignment Algorithms on Children’s Speech. Journal of Speech, Language, and Hearing Research, 64, 2213–2222. 10.1044/2020_JSLHR-20-00268. [📄 Preprint.]

Sakash, A., Mahr, T., & Hustad, K. C. (2021). Validity of Parent Ratings of Speech Intelligibility for Children with Cerebral Palsy. Developmental Neurorehabilitation, 24, 98–106. 10.1080/17518423.2020.1830447.

Mahr, T., Rathouz, P. J., & Hustad, K. C. (2020). Longitudinal Growth in Intelligibility of Connected Speech From 2 to 8 Years in Children With Cerebral Palsy: A Novel Bayesian Approach. Journal of Speech, Language, and Hearing Research, 63, 2880–2893. 10.1044/2020_JSLHR-20-00181.

Hustad, K. C., Mahr, T., Natzke, P. E. M., & Rathouz, P. J. (2020). Development of Speech Intelligibility Between 30 and 47 Months in Typically Developing Children: A Cross-Sectional Study of Growth. Journal of Speech, Language, and Hearing Research, 63, 1675-1687. 10.1044/2020_JSLHR-20-00008.

Natzke, P. E. M., Sakash, A., Mahr, T., & Hustad, K. C. (2020). Measuring Speech Production Development in Children With Cerebral Palsy Between 6 and 8 Years of Age: Relationships Among Measures. Language, Speech, and Hearing Services in Schools, 51, 882-896. 10.1044/2020_LSHSS-19-00102.

Hustad, K. C., Mahr, T., Broman, A. T., & Rathouz, P. J. (2020). Longitudinal Growth in Single-Word Intelligibility Among Children With Cerebral Palsy From 24 to 96 Months of Age: Effects of Speech-Language Profile Group Membership on Outcomes. Journal of Speech, Language, and Hearing Research, 63, 32–48. 10.1044/2019_JSLHR-19-00033.

Sakash, A., Mahr, T., Natzke, P. E. M., & Hustad, K. C. (2020). Effects of Rate Manipulation on Intelligibility in Children With Cerebral Palsy. American Journal of Speech-Language Pathology, 29, 127–141. 10.1044/2019_AJSLP-19-0047.

Geller, J., Winn, M. B., Mahr, T., & Mirman, D. (2020). gazeR: A Package for Processing Gaze Position and Pupil Size data. Behavior Research Methods. 10.3758/s13428-020-01374-8.

Venker, C., Pomper, R., Mahr, T., Edwards, J. R., Saffran, J. R., & Ellis Weismer, S. (2020). Comparing Automatic Eye Tracking and Manual Gaze Coding Methods in Young Children with Autism Spectrum Disorder. Autism Research, 13, 271–283. 10.1002/aur.2225.

Mahr, T., & Edwards, J. R. (2018). Using language input and lexical processing to predict vocabulary size. Developmental Science. 10.1111/desc.12685. [🧪 Data and scripts on GitHub.]

Law, F., II, Mahr, T., Schneeberg, A., & Edwards, J. R. (2016). Vocabulary size and auditory word recognition in preschool children. Applied Psycholinguistics. 10.1017/S0142716416000126.

Mahr, T., McMillan, B. T. M., Saffran, J. R., Ellis Weismer, S., & Edwards, J. R. (2015). Anticipatory coarticulation facilitates word recognition in toddlers. Cognition, 142, 345–350. 10.1016/j.cognition.2015.05.009. [🧪 Data, scripts, stimuli on GitHub.]

Presentations

Invited talks

Mahr, T. (2018, March). Development of word recognition in preschoolers. Presentation for the UW-Madison Communication Sciences & Disorders Professional Seminar, Madison, WI.

Mahr, T. (2016, September). Bayesian Regression Models with RStanARM. Presentation for the Madison R Users Group, Madison, WI. [🧪 GitHub repository.]

Mahr, T. (2015, March). Let the data flow: Pipelines in R with dplyr and magrittr. Presentation for the Madison R Users Group, Madison, WI. [🧪 GitHub repository.]

Mahr, T. (2014, October). Using eyetracking to study toddlers’ sensitivity to coarticulation during word recognition. Presentation for the UW-Madison Communication Sciences & Disorders Professional Seminar, Madison, WI.

Conference talks

Mahr, T., Natzke, P. E. M., & Hustad, K. C. (2019, November). Intelligibility in Connected Speech in Children with Cerebral Palsy. Technical Research Session at the Annual Conference of the American Speech-Language-Hearing Association, Orlando, FL.

Mahr, T. (2019, April). bayesplot: Diagnostic plots for Bayesian models. Presentation at SatRday Chicago. [🧪 GitHub repository.]

Mahr, T., & Edwards, J. R. (2016, November). Lexical processing efficiency in preschool children: Influences of speech perception and inhibitory control. Presentation at the 41st annual Boston University Conference on Language Development, Boston, MA.

Mahr, T., McMillan, B. T. M., Saffran, J. R., & Edwards, J. R. (2014, November). Toddlers are sensitive to anticipatory coarticulation during word recognition. Presentation at the 39th annual Boston University Conference on Language Development, Boston, MA.

Mahr, T., McMillan, B. T. M., Saffran, J. R., & Edwards, J. R. (2014, September). Are toddlers sensitive to anticipatory coarticulation during word recognition?. Presentation at the 19th annual Mid-Continental Phonetics & Phonology Conference, Madison, WI.

Coauthored talks (i.e., I didn’t talk, but probably did stats and made figures)

Mahr, T., & Edwards, J. R. (2017, November). Spoken word recognition of children with cochlear implants. Presentation at the 42nd annual Boston University Conference on Language Development, Boston, MA. [🧪 Data, scripts, slides on GitHub.]

Venker, C., Mahr, T., Premo, E., Saffran, J. R., Edwards, J. R., & Ellis Weismer, S. (2016, November). Comparing Automatic Eye Tracking & Manual Gaze Coding in Children with Autism Spectrum Disorder. Technical Research Session at the Annual Conference of the American Speech-Language-Hearing Association, Philadelphia, PA.

Law, F., II, Mahr, T., & Edwards, J. R. (2015, November). Exploring effects of expressive vocabulary size and maternal education on lexical processing by preschoolers using the visual world paradigm. Presentation at the 40th annual Boston University Conference on Language Development, Boston, MA.

Edwards, J. R., & Mahr, T. (2015, November). Speech perception and spoken word recognition in young children. Presentation at the 170th Meeting of the Acoustical Society of America, Jacksonville, FL. 10.1121/1.4933949.

Posters

Mahr, T., & Hustad, K. C. (2022, February). Lexical predictors of single-word intelligibility in young children’s speech. Poster presented (by K. C. Hustad) at the Conference on Motor Speech, Charleston, SC. [🧪 Poster on GitHub.]

Sakash, A., Mahr, T., & Hustad, K. C. (2020, November). Parent Estimates of Intelligibility in Cerebral Palsy: Relationship with Objective Measurement within Speech Severity Groups. Proposal accepted at the Annual Convention of the American Speech-Language-Hearing Association, San Diego, CA (Convention canceled).

Mahr, T., Kawabata, K., Mathad, V. C., Berisha, V., Tang, S., Vradelis, H., Liss, J., & Hustad, K. C. (2020, February). Performance of forced-alignment algorithms on children’s speech. Poster presented at the Conference on Motor Speech, Santa Barbara, CA. [🧪 Poster on GitHub.]

Hustad, K. C., Mahr, T., & Natzke, P. E. M. (2019, November). Speech Intelligibility Development Between 36–47 Months in Typically Developing Children. Poster session presented at the Annual Conference of the American Speech-Language-Hearing Association, Orlando, FL. [🏆 Meritorious poster award.]

Vradelis, H., Tang, S., Kawabata, K., Mahr, T., Berisha, V., Liss, J., & Hustad, K. C. (2019, November). Automatic Speech Recognition: An Objective Measure of Segmental Integrity in Children’s Connected Speech. Poster session presented at the Annual Conference of the American Speech-Language-Hearing Association, Orlando, FL.

Mahr, T., Natzke, P. E. M., & Hustad, K. C. (2019, June). Intelligibility in multiword utterances in children with cerebral palsy. Poster session presented at the annual Symposium on Research in Child Language Disorders, Madison, WI. [🧪 Poster on GitHub.]

Mahr, T., & Edwards, J. R. (2018, June). Development of familiar word recognition in preschoolers. Poster session presented at the annual Symposium on Research in Child Language Disorders, Madison, WI. [🧪 Poster on GitHub.]

Erskine, M. E., Mahr, T., & Edwards, J. R. (2017, November). Understanding the effects of dialect familiarity on lexical processing efficiency in preschool children using the visual world paradigm. Poster session at the 42nd annual Boston University Conference on Language Development, Boston, MA. [🧪 Data, scripts, poster on GitHub.]

Erskine, M. E., Mahr, T., & Edwards, J. R. (2017, November). The Influence of Dialect Familiarity on Preschool Children’s Spoken Word Recognition. Poster session presented at the Annual Conference of the American Speech-Language-Hearing Association, Los Angeles, CA.

Mahr, T., Venker, C., Premo, E., Ellis Weismer, S., Saffran, J. R., & Edwards, J. R. (2016, June). Preschoolers with autism treat nonwords and mispronunciations differently. Poster session presented at the annual Symposium on Research in Child Language Disorders, Madison, WI.

Mahr, T., & Edwards, J. R. (2015, November). Using language input and lexical processing to predict vocabulary size. Poster session presented at 56th Annual Meeting of the Psychonomic Society, Chicago, IL.

Erskine, M. E., Mahr, T., Munson, B., & Edwards, J. R. (2015, June). The lexical restructuring hypothesis: Two claims of phonological awareness evaluated. Poster session presented at the annual Symposium on Research in Child Language Disorders, Madison, WI.

Mahr, T., Law, F., II, & Edwards, J. R. (2014, June). The influence of home language input and lexical processing efficiency on vocabulary size in 3-year-olds. Poster session presented at the annual Symposium on Research in Child Language Disorders, Madison, WI.

Mahr, T., & Seidel, C. (2014, February). Comparison of the GFTA-2, KLPA-2, HAPP-3 and BBTOP for different consonant error profiles. Poster session presented at the annual conference of the Wisconsin Speech-Language Pathology and Audiology Association, Middleton, WI.

Seidel, C., & Mahr, T. (2013, November). A quantitative comparison of articulation assessments for different consonant error profiles. Poster session presented at the Annual Conference of the American Speech-Language-Hearing Association, Chicago, IL.

Mahr, T., & Edwards, J. R. (2013, June). Do orienting stimuli create additional task demands in the looking-while-listening paradigm?. Poster session presented at the annual Symposium on Research in Child Language Disorders, Madison, WI.

Teaching

Lecturing

  • Guest lecture on Bayesian regression for graduate statistics course in psychology department.
  • Guest lecture on phonological disorders for introductory communicative disorders course.
  • Guest lecture and accompanying online exercise on assessment of speech sounds for phonetics and phonological disorders course.

Clinical experience

These are positions and roles I worked in as a student speech-language clinician.

  • 2013–2014: Speech-language diagnostics (eventually as a long-term substitute for position), Middleton Cross Plains School District.
  • 2013: Pediatric voice clinic, American Family Children’s Hospital.
  • 2012: Fluency clinic, UW-Madison Speech & Hearing Clinic.
  • 2012: Telling Life Stories program (helping individuals with aphasia create a scrapbook biography), UW-Madison Speech & Hearing Clinic.
  • 2012: Transgender voice clinic, UW-Madison Speech & Hearing Clinic.
  • 2011: Phonology clinic, UW-Madison Waisman Center.

Awards

2017–18, 2012–13: Supported by NIH Training Grant to Susan Ellis Weismer: 5-T32-DC5359, Interdisciplinary Research in Speech–Language Disorders.

2016: Jean Berko Gleason Award for highest scored student submission at the 41st Boston University Conference on Language Development.

2014: Paula Menyuk Travel Award recipient at the 39th Boston University Conference on Language Development.

2014: Emma Allen Scholarship. Given by the Dept. of Communication Sciences and Disorder at UW–Madison.

2013–15: Supported by NIH Training Grant to Maryellen MacDonald: 2-T32-HD049899, Training in Language: Acquisition and Adult Performance.

2012: Students Preparing for Academic-Research Careers (SPARC) Award. Given by the American Speech-Language-Hearing Association.